Problem 140 - Objective Biology for NEET

Question

Cambium, which produces cork is known as (a) Phelloderm (b) Phellogen (c) Periblem (d) Periderm

Step-by-Step Solution

Answer

The correct answer is (b) Phellogen

Step 1: Understand the question

The question asks: Cambium, which produces cork is known as (a) Phelloderm (b) Phellogen (c) Periblem (d) Periderm

Step 2: Apply Biology knowledge

Using fundamental Biology concepts to analyze the problem.

Step 3: Formulate the answer

The correct answer is (b) Phellogen

Step 4: Conclude

The answer is: The correct answer is (b) Phellogen

Key Concepts

Cambium

Cambium is a type of plant tissue found within the stems and roots of most vascular plants. It is responsible for the secondary growth that increases the thickness of stems and roots.

There are two main types of cambium: vascular cambium and cork cambium (also known as phellogen). These tissues are called meristematic tissues, which means they are regions of active cell division.

• Vascular cambium generates new vascular tissues (xylem and phloem), aiding in the transportation of water, nutrients, and food throughout the plant.
• Cork cambium or phellogen produces cork cells that contribute to the formation of the bark.

The activity of cambium results in the thickening of stems and roots and serves to protect the plant while aiding in the transport of nutrients and water.

Phellogen

Phellogen, also known as cork cambium, is a type of meristematic tissue that forms part of the plant's periderm. It plays a vital role in the protection of plants.

Phellogen is located between the bark and the inner living tissues of a plant, where it functions as a lateral meristem.

• Phellogen initiates the development of cork cells and phelloderm, which together form the periderm
• It has the unique ability to divide and produce new tissue to replace the epidermis during secondary growth

By generating cork, phellogen helps in protecting the plant from physical injuries and pathogens.

It also plays a critical role in preventing water loss.

Cork Formation

Cork formation is an essential process in the development of a plant's protective outer layer, also known as the periderm. This process is driven by the phellogen or cork cambium.

During cork formation, phellogen divides to produce cork cells on the outer side and sometimes phelloderm cells towards the inner side.

• Cork cells develop an impermeable layer of suberin, a substance that makes them waterproof and fire-resistant.
• The accumulation of dead cork cells contributes to the thickness and texture of the bark.

The production of cork helps safeguard the plant against mechanical damage, desiccation, and infection.

Additionally, cork is crucial in supporting gas exchange through lenticels—tiny openings present on the bark.

Plant Tissues

Plant tissues are groups of cells specialized to perform unified functions in plants. They are generally categorized into four major types: protective, meristematic, vascular, and ground tissues.

Understanding the variety of plant tissues is essential for recognizing how plants grow and sustain themselves:

• Protective tissues, like the epidermis and periderm, protect the plant from the external environment.
• Meristematic tissues continually divide to enable growth and regeneration of plant parts.
• Vascular tissues (xylem and phloem) are responsible for the transport of water, minerals, and organic nutrients throughout the plant.
• Ground tissues provide support, store nutrients, and carry out photosynthesis.

Each type of tissue plays a strategic role in ensuring a plant's growth and survival, working together to maintain the health and functionality of the plant overall.